Intradermal testing after severe histamine reactions to intravenous drugs used in anaesthesia

In a series of patients who suffered severe histamine mediated reactions to induction agents and muscle relaxants, intradermal testing enabled the drug involved to be distinguished. The correct use of intradermal testing to give reliable results is discussed and a protocol described. Prausnitz Kustner testing was of little help in confirming the results. A number of patients tested showed high levels of immunoglobulin G (IgG) and it is believed that IgG mediated anaphylaxis may be the mechanism responsible for reactions that have been previously described as anaphylactoid or direct chemical histamine release.